fix: unnecessary API call when writing collection of DataPoints

[bednar]

Closes #112

Proposed Changes

Fixed unnecessary API call when writing collection of DataPoints.

Checklist

• CHANGELOG.md updated
• Rebased/mergeable
• A test has been added if appropriate
• dotnet test completes successfully
• Commit messages are in semantic format
• Sign CLA (if not already signed)

[codecov-commenter]

Codecov Report

Merging #113 into master will increase coverage by 0.01%.
The diff coverage is 20.00%.

@@            Coverage Diff             @@
##           master     #113      +/-   ##
==========================================
+ Coverage   15.63%   15.64%   +0.01%     
==========================================
  Files          50       50              
  Lines        5002     4997       -5     
  Branches      253      253              
==========================================
  Hits          782      782              
+ Misses       4199     4194       -5     
  Partials       21       21              

Impacted Files	Coverage Δ
Client/WriteApiAsync.cs	6.40% <20.00%> (+0.24%)	⬆️

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